He described publicly: “Squalor, filth, the air hanging heavy with the smell of drugs, a dilapidated physical environment, a sense of great instability of feeling that of any time violence could break out.”

Bambos Charalambous MP said there was a 'level of corruption' among some HMP Birmingham staff.

Two of Mr Clarke’s own team discovered the full extent of HMP Birmingham’s ills during their visit to compile the damning dossier.

Their vehicles were torched on the car park, along with seven others belonging to officers.

In an exclusive interview following an October 29 visit by the Justice Committee, Mr Charalambous stressed that interim governor Paul Newton has made great improvements.

But he warned: “Can those short-term improvements be sustained in the long term?

"The jury is still out.”

The politician’s comments come on the eve of HMP Birmingham’s Independent Monitoring Board’s report on the establishment, which will be published on Monday.